In Cable TV and other RF signal distribution systems, it is usually required to tap off RF energy from a main distribution coaxial cable for subscriber service through a drop feed cable. A known tap off device to accomplishing this is a multi-tap.
A variety of tap values are available in order to deliver the correct signal level to the service drop regardless of signal level in the transmission cable at that particular point in the system.
A multi-tap consists of a removable tap plate and a housing. The tap plate and housing must be installed in the manner to be completely hermetically sealed so that moisture does not penetrate into the device.
When, however, additional services such as those that provide telephone service to a user, the power source to energize the necessary equipment will be provided by the cable system through the same coaxial cable carrying both AC power and the RF signal. Within the tap, an RF signal is tapped off to appropriate RF connectors, which are an integral part of the tap plate. AC power is provided through the IDC (Insulation Displacement Connector) connector terminal inside the tap.
Typically a coaxial cable with an F-Type connector is connected to the tap RF ports to tap off an RF signal to a subscriber TV set, and a pair of wires are connected to the AC connector terminal of the tap to tap off AC power to subscriber equipment.
Thus it is necessary that ends of the leads for carrying power to the user be inserted into the hermetically sealed junction box, but it has been difficult to do this in such manner as to preserve the hermetical seal. For example, such a junction box can be a multi-tap for cable TV. One method has been to simply pass the leads between the cover and the body of the box in the hope that the gasket between them will provide the seal. Unfortunately, however, the gasket material does not flow completely around the leads and therefore cannot provide a hermetic seal. The problem gets worse each time the box is opened. Typically, the leads carry AC power from the multi-tap for example, to a subscriber or user.
Furthermore, connection between a terminal in the junction box and a lead from the special cable that has been inserted into the junction box has heretofore been effected by an IDC connector within the box having a terminal for connection to circuits, a blind input port into which the lead is inserted, and mechanically operable means for cutting through the insulation of the lead so as to connect it to the terminal.
One of the problems encountered is that it has been difficult for a cable installer to know whether or not the connection has been made because of the possibility that the lead is not properly located within the IDC connector. It might, for example, be deflected so as not to reach the position where its insulation will be cut so as to make the desired connection to the terminal. This problem is emphasized by deleterious conditions under which the connection is sometimes made.